Apparatus for distilling volatile substances



F. G. DU PONT. APPARATUS FOR DISTILLING VOLATILE SUBSTANCES.

No. 503,586. Patented Aug. 22, 1893.

A (No Model.)

Aim

UNITED STATES PATENT OFFICE.

FRANCIS G. DU PONT, OF WILMINGTON, DELAWARE.

APPARATUS FOR DISTILLING VOLATILE SUBSTANCES.

SPECIFICATION forming part of Letters Patent No. 503,586, dated August22, 1893.

Application filed April 14, 1893. Serial No. 470,347. (No model.)

To all whom, it may concern.-

Be it known that I, FRANCIS G. DU PONT, a citizen of the United States,residing at Wilmington, in the county of New Castle and State ofDelaware, have invented certain new and useful Improvements in Apparatusfor Distilling Volatile Substances; and I do hereby declare thefollowingto be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

My invention relates to improvements in apparatus for distillingvolatile substances, and it consists in an improved form of still,especially designed to be used in the separation of the solvent from thegrains of explosive formed by the process of making smokeless powderdescribed in the joint application of myself and Pierre S. du Pont,filed December 21, 1892, Serial No. 455,901, which will be hereinafterfully described, and particularly pointed out in the claims. In saidapplication, the process of making smokeless powder is described,whichconsists in suspending finely divided nitro-cellulose in a suitableliquid, granulating the same by adding thereto in proper proportions a,suitable solvent of nitro-cellulose, and finally removing the excess ofsolvent, and treating the grains so as to harden and solidify them. As apreliminary or accompanying step to such solidification and hardening ofthe grains, it is necessary to remove the excess of solvent from thegrains, and it is the object of my invention to provide a form of still,which will enable this operation to be carried on easily and rapidly;whichwill enable the solvent recovered by the distillation to becollected in such a manner as to allow easy measurement of its amount,and therefore of the extent to which the distillation has proceeded; andwhich will enable the level of the contents of the still to beautomatically maintained at or near a certain point, thus facilitatingthe operation of distillation. This object I attain by the use of a mainstill, provided with means for condensing and collecting the vaporsformedtherein, and an auxiliary reservoir or collector used inconnection therewith, Which is so arranged as to have the distillatefrom the main still delivered into it, and is further connected to thestill by a pipe jointed to the 'still at a point slightly above thelevel of the liquids in the same, and to the reservoir at a point belowthe level of discharge of the distillate, the connection being such thatafter the level of the contents of the reservoir reaches that of thesaid overflow pipe, any further addition to its contents is siphonedover to the main still. The distillate obtained by the special use ofthe still herein described consists of the solvent vaporized from thegrains of explosives which are placed in the tank, and the water whichis added to the grains. Of the two-fold distillate thus obtained, thedistilled solvent, being heavier than the condensed water, settles tothe bottom of the reservoir, and can be drawn off and measured at anytime, thus permitting an accurate quantitative determination of suchdistillate to be obtained. The distilled water is, in the manner abovestated, automatically returned to the still, and as the amount ofdistilled solvent is much less than that of the distilled water, and asnearly all of such water is returned to the still, the level of thecontents of the same is maintained practically constant.

The apparatus forming my invention is fully represented in the drawingsaccompanying and forming a part of this application, which is asectional view of the still, the reservoir, and the parts used inconnection therewith.

Referring to the drawings, A represents the still, which is of anyconvenient size and construction, and has around its lower portion, B,an encircling steam jacket, provided with steam inlet and outlet pipes.The pipe 0, at the apex of the conical bottom of the still, serves forthe introduction and removal of material. The still is provided with aconical top, D, around the outer shell, F, of which is placed the jacketG, which is provided with water inlet and outlet pipes, and betweenwhich, and the said shell F, a stream of cold water is constantlyflowing when the still is in operation.v The outlet H is for theconduction of vapors escaping from the still to any suitable condenser,which is so arranged that the fall of the pipes leading to the same isbackward into the still, so as to drain condensed products into thestill head. Inside I distillate.

"admission of air.

still as rapidly as formed.

of the shell F and of a form corresponding'to thatof'saidshell, issuspended the in nershell which may be drawn from time t'o'time thesolvent which collects in said bottom, the" solvent being heavier thanwater. The said reservoir is also provided with an air-tight closureatits top, and a stop cock M for the Besides the connection atforded bypipe J, the reservoir is also connected with the still by the overflowpipc L, which is joined to the still at a pint a little abovethe levelof the contents of the same, and entersthe reservoir at a point belowthe level of discharge of the distillate, thus allowingthewater, whichis the lighter product of the distillation, to flow back into the mainCocks'are provided in the two pipes connecting the still andthereservoir, so that in case a vacuum is used in connection with theoutlet pipe of.

. the still, they may be closed, and air admitted ,L-Way into theannular trough I, and from thence, by pipe J, into the reservoir K. Allof the distillateis thus condensed, collected in the annular trough,"anddelivered into-the reserfvoin, When the distillate'areaches thereservoir, a separation of the products forming the sametakes place, theheavier solvent falling to the bottom of the reservoir, and the water,after the level of the contents of the "reservoir has reached that ofthe pipe L, passing over into the main" still. From time to time, thesolvent should be drawn off from the reservoir, in order that too muchof the solvent may not gather therein, and while this operation isbeing'performed, the cooks to pipes J andL should be closed, and-thecock M opened, so that the ordinary atmospheric pressure may; exist inthe'reservoir. In this manner, the exact quantity of solvent distilledfrom the grain of the still may be ascertained,and thus it canbedete'rmin'ed when the distilling'operation has proceeded far enough.The solvent recovered is perfe'etlypure, and is in condition to be usedover again in the pro duction of a fresh'quantity of explosivegrain.

As the amountof solvent recovered is small in proportion to th'atof thewater distilled to: the reservoir through the cock'M,restoringatmospheric pressure, and enabling the-heavy liquid at the bottom of thereservoir to be drawn off from time to time as needed.

The operation of my still is as follows a portion of the grain producedby the process described in the application above referred to, and thesolvent found in connection the're-i with,'is placed in the still, andwater is added about'to't'he level of the jacket. A vacuum I pump isthen connected to pipe H, and steam of the contents of the same, andpreventing the'temperature of the same rising above The vacuum is notnecessary,however,in the ot my process. The vapors thus produced tion ofthe same will be condensed on the in- A by pipe J. The uncondensedportion of "the l whence it will be conveyed to the reservoirK vaporspasses under the edge of the inner cone, and up between the outer'andinner (01168.

' by Letters Patent, is-

over into the reservoir, andfasthe amount of such solvent is smallincompar isonwi'th the .amount of wateninthestil'hthe automatic return ofthe water to .the'still maintains the level of the' contentsof the samepractically constant. interrupt the operation of the still, andintroduce a fresh-supply ofwater'intothe same.

It isthus unnecessary to at-times After the siphonin'gjaction hascommenced,

the then level of the contents of ithestill is I maintained almostabsolutely constant, a circulated through the jacket surrounding the 1bottom of. the still. The object of using the I vacuum is to decreasethe'atmospheric pressure in the still, thus hastening the ebulliti'onslight deviation being due to theremoval 0f the distilled solvent. Thetime ofcommencement of such si phonin gaction'depends largely upon therelative 'propor'tions of th-e still and reservoir, and the position "ofthe overflow jpipe in said reservoir. Y

the desired point, which is,when treating the 1 grains of explosive,about 140 Fahrenheit.

It is evident that by prolonging the siphon pipe L to the bottom of thereservoir, and by V '5 providing a side outlet for the reservoir, Itreatment of all classes of volatile substances, I I and its use doesnotform an essential portion may'use my apparatus for the'separation-andrecovery'of the: lighter of the two products of j distillation,"returning a the heavier product riseto the conical, top of the still,and a porthrough pipe L to the still, and drawing oif the lighterproduct through the side outlet of the reservoir, and I do not confinemyself to the separation and recovery of the heavier product ofdistillation. v I

I do not confine myself to the eXa'ct form and proportions of theapparatu'sfdescribed herein, or to theuse of the apparatus in the Sincethe outer cone is surrounded.

processof manufacture of smokeless powder.

"What I claim as ne 1. In a still, the combination with the conianddesire to secure cal top of the same provided with refrigerating means,of an inner conical shell suspended within the top, an annular trougharranged so as to collect the distillate, and a delivery pipe for saidtrough, substantially as described.

2. In an apparatus for distilling volatile substances, the combinationwith a main still provided with a conical top having refrigeratingmeans, an inner conical shell suspended Within said top, and an annulartrough arranged so as to collect the distillate, of a reservoir forreceiving the distillate, provided with an outlet for one of thecondensed products, means for automatically returning the othercondensed product to the main still, and a pipe leading from the annulartrough of the still to the reservoir for conducting the distillate tothe same, substantially as described.

3. In an apparatus for distilling volatile substances, the combinationwith a main still provided with a conical top having refrigerating meansan inner conical shell suspended within said top, and an annular trougharranged so as to collect the distillate, of a reservoir provided withan outlet at its bottom, a pipe conducting the distillate to thereservoir, and a pipe connecting the reservoir with the still at a pointabove the level of the liquids in the still, substantially as described.

4. In an apparatus for distilling volatile substances, the combinationwith a main'still provided with a conical top having refrigeratingmeans, an inner conical shell suspended within said top, and an annulartrough arranged so as to collect the distillate, a reservoir having anoutlet opening at its bottom, a pipe conducting the distillate to thereservoir, and a pipe connecting the still with the reservoir at a pointabove the level of the liquid in the still, and below the point ofentrance of the distillate, substantially as described.

5. In an apparatus for distilling volatile substances, the combinationwith a main still A, provided with the inner shell E and annular troughI, of a reservoir K, having an outlet opening at its bottom for theheavier condensed .product, and connected to said still by thedistillate-discharge pipe J, and the overflow pipe L, substantially asdescribed.

In testimony whereof I affix my signature in presence of two witnesses.

V FRANCIS G. DU PONT.

W'itnesses: V

FRANCIS I. DU PONT, ELIZA SIMoNs.

